I've read through the entire 'Speaker Building 101' (thread from mid-2001) but couldn't really find a answer clear on this. Port tuning for a single speaker is relatively easy given Vb, Fb, and the T/S values, etc. How does a multiple speaker cabinet affect port tuning though? (assertion: all speakers are the same size) For example (just throwing out #s), suppose a 10" driver requires (2) 2.75" ports @ 3" length. Would two 10" drivers require (4) ports, three would require (6) ports, etc? My instincts say that tuning is on a per driver basis, so combine the port area of a single driver w/ the number of drivers, then work with this result to get workable ports. Can anyone clarify this for me?